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Nitroxyl Peptides as Catalysts of Enantioselective Oxidations
Author(s) -
Formaggio Fernando,
Bonchio Marcella,
Crisma Marco,
Peggion Cristina,
Mezzato Stefano,
Polese Alessandra,
Barazza Alessandra,
Antonello Sabrina,
Maran Flavio,
Broxterman Quirinus B.,
Kaptein Bernard,
Kamphuis Johan,
Vitale Rosa Maria,
Saviano Michele,
Benedetti Ettore,
Toniolo Claudio
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020104)8:1<84::aid-chem84>3.0.co;2-n
Subject(s) - chemistry , enantioselective synthesis , dipeptide , stereochemistry , nitroxyl , diastereomer , catalysis , amino acid , organic chemistry , biochemistry
The achiral, nitroxyl‐containing α ‐amino acid TOAC (TOAC=2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐4‐amino‐4‐carboxylic acid), in combination with the chiral α ‐amino acid C α ‐methyl valine [( α Me)Val], was used to prepare short peptides (from di‐ to hexa‐) that induced the enantioselective oxidation of racemic 1‐phenylethanol to acetophenone. The best catalyst was an N α ‐acylated dipeptide alkylamide with the −TOAC‐( α Me)Val− sequence folded in a stable, intramolecularly hydrogen‐bonded β ‐turn conformation with large, lipophilic (hydrophobic) N‐ and C‐terminal blocking groups. We rationalized our findings by proposing models for the diastereomeric intermediates between ( R )‐[and ( S )]‐1‐phenylethanol and the catalyst Fmoc‐TOAC‐ L ‐( α Me)Val‐NH i Pr, based on the X‐ray diffraction structure of the latter.